In the last days, i have been doing some cleanup
amongst various electronic. And in the prosses i have
found some cd drives. (just the drive) How to ID them,
they haven`t got any labeling.

btw. i also found two cdp`s: marantz cd4000 & cd53.
the 4000 is fully working, but the drive in the 53. is non-working.
(Won`t read/load)
what drive is it in the 53. (standard modell)
and what is the quality of this cdp.
(i know, both are cheap players, but is it something worth fixing,
upgrade on.)

Hi,
It's CDM12.1, widely used in Marantz's CDP in that period. If it's spinning the disc but alway show 'No Disc'. You may try to adjust the POT at the Laser Module first (CW turn).
If it's still not work, then change it. I though, it's not hard to find them somewhere in Europe. Good luck.
Regards,
Art

TnX. for the replies.
@Art. The symtom are similar to what you describe.
The CD is spinning. nothing wrong there.
The tray open/closes fine.
The thing is that after i press "play" or any button,
the display shows the right command, but it simply will not read.
After showing "play" for awhile, the drive stops.

That happen to me too. I try to tune the small POT (VR) at the laser pickup. And it's work. I though it's increase the laser level or increase the sensitivity of sensor. A year after that, the laser pickup completely dead, then I buy the new one to substitute.

TnX. for the feedback guy`s,
will try it out, and see if it`s the laser that`s foulty or not.
a new transport/drive unit is out of the question,
Do anyone of ya know anything about the
circuit quality and DAC of the 53.

Use the search function and look for "cd 63" or similar - there's plenty info waiting to be read. As far as I remember, there is a lot of noise on the supply rails to the different stages. You could/should additionally go for a more precise clock (Tent, Kwak or lcaudio). I've got kwak7's in both players I own and it is an unbelievable improvement. The conversion chip of the marantz is mediocre, I think. I once owned an unmodded cd63 but was feeling comfortable with it's warm sound.

If the housing is ok, you might consider selling it at ebay. There are a lot of people searching cd53/63 for modding purposes. I sold mine with a totally dead laser drive board for 40euros. The guy repaired & modded it and sold it for far more. So we both were happy with the deal...

btw: the cdm12.x is very sensitive concerning dust on the metallic bar where the laser unit glides on. You'll have to carefully clean and re-oil it. Otherwise the player skips on the last couple of songs.